Flame resistant organic textiles and method of production



United States PatentO'i FLAME RESISTANT ORGANIC TEXTILES AND METHOD OF PRODUCTION Leon H. Chance, George L. Drake, Jr., and Wilson A. Reeves, New Orleans, La., assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Original application June 5, 1956, Serial No. 589,561. Divided and this application April'24, 1957, Serial No. 661,986

Claims. (Cl. 117-136) (Granted under Title 35, U. S. Code (1952), sec. 266) of being produced by the reaction of a l-aziridinyl phosphine oxide or sulfide (e. g. a compound that contains at least two l-aziridinyl groups attached to pentavalent phosphorus), with a polyhydric alcohol of the formula (HO),,R where x is an integer of two or more and R is an alkyl or aryl group.

We have discovered that compounds that contain at least two l-aziridinyl groups attached to pentavalent phosphorus atoms react with alcoholic compounds (e. g. compounds that contain at least two HO groups) to produce polymers. Such polymers contain the reoccurring connecting structures wherein the phosphorus atoms are pentavalent and OR is an alkoxy group.

Such polymers can be produced in the form of, solid synthetic resins. They can be deposited on the surfaces and/or in the interstices of hydrophilic fibrous organic materials, i. e.,- organic materials which absorb or adsorb water. When such resins are deposited, they reduce the combustibility of hydrophilic fibrous organic materials and resist removal by laundering and the like chemical treatments. Such resins can be deposited on the surfaces of non-hydrophilic materials to form flame resistant coatings.

l-aziridinyl phosphine oxides or sulfides suitable for use in this invention are compounds which contain at least two l-aziridinyl groups, (CH N, attached to pentavalent phosphorus atoms. The compounds used in this invention may be represented by the following structure:-

Patented Jan. 20, 1959 ice M wherein X is or a dialkyl amine group such as Suitable polyhydric alcohols for use in this invention include aliphatic and aromatic alcohols that contain two or more OH groups. The alcohols of the following list are typical alcohols suitable for use in this invention, but the invention is not limited to these: ethylene glycol,

glycerol, 2 butene 1,4 diol, pentaerythritol, glucose,

triethanolamine, diethanolamine, tris(hydroxymethyl)' aminomethane, resorcinol, and phloroglucinol.

The aziridinyl compounds used in this invention also react with thio alcohols, that is, compounds that contain 21 -SH group. An example of a thio alcohol that reacts readily with the aziridinyl compounds described here is 1,6-hexanedithiol, HS(CH SH.

Polymers provided by this invention can be produced in acidic, neutral, and alkaline conditions. They can be produced in the form of liquids or solids and can be molded by the conventional techniques of molding thermosetting resins. These polymers are valuable materials for use in production of: molded synthetic articles, such as buttons, electrical insulators and the like; synthetic coatings such as protective coatings, and paints and the like having reduced flammability; paper treating resins, textile resins; medicinal agents; lubricants; leather treating agents; insoluble starch; modification of pectic substances and the like.

The polymers provided by this invention are preferably prepared by gently heating an aziridinyl phosphine oxide or sulfide and a polyhydric alcohol until polymerization occurs. The reaction can be carried out in a solvent or in the absence of solvent. The preferred relative amounts of aziridinyl compound and alcohol used to polymerize can be calculated by conventional methods by assumingthat: (1) for each aziridinyl group present in the compound, the functionality is one (e. g. if two aziridinyl groups are present, the functionality is two), (2) that the functionality of the alcoholic compound is equal to the number of OH groups present in the compound. These reactions can be carried out without catalysts or in the presence of neutral carbonates. like calcium carbonate, alkali carbonates like sodium carbonate, alkali metal hydroxides, tertiary amines, and bases in general or in the presence of mineral acids. Neutral or slightly alkaline conditions are preferred.

formed by reacting the monomeric compounds until partial polymerization occurs and curing the impregnated materials at the temperatures conventionally used for curing fibrous organic materials.

Surface active agents, water repellents, and other textile treating agents may be incorporated into the aqueous or emulsion treating media to modify the treated textiles. Surface active softening agents improve tear strength of cotton and rayon fabrics.

The process of this invention can be used to reduce the combustibility of substantially any hydrophilic fibrous material such as cotton, rayon such as viscose rayon, ramie, jute, wool, paper, cardboard and the like materials which can be impregnated with a liquid and dried or cured.

Where a textile is being impregnated, it is of advantage to remove excess impregnating liquor by passing the textile through squeeze rolls prior to drying or curing the impregnated textile. It is also advantageous to dry the textile at about 70 to 110 C. before it is cured at a temperature of from about 100 to 170 C.

The degree of flame resistance imparted to a textile by these phosphorus and nitrogen containing resins can be varied from a low degree to a very high degree by varying the amount of polymer put in the textile.

Some advantages of flameproofing textiles in accordance with this invention are: textiles treated by this process are flame resistant, glow resistant, shrink resistant, and.

rot. and mildew resistant; the effects of the treatment are permanent, and resistant to laundering, dry cleaning, and boiling alkali solutions; cellulosic textile inaterials retain a very high percentage of their tear and tensile strength.

The following examples are illustrative of. details of. the invention. The term parts or percent refers to parts or percent by weight. tris(1-aziridinyl)phosphine oxide and the term APS refers to tris(1-aziridinyl)phosphine sulfide.

Example I Pentaerythritol with APS.A white brittle polymer was prepared by heating a solution made by dissolving 25 parts of pentaerythritol in 200 parts of warm water (about 30-35 C.) then dissolving 25 parts of APS. One half of the solution was heated on a steam bath for 30 minutes then spread out into a thin layer and heated for 1 minutes at 145 C. The. resulting polymer was a very light colored product that was insoluble in water and in organic solvents. It contained sulfur phosphorus and nitrogen and was highly flame resistant.

The other half of the solution prepared above was used to pad cotton sateen fabric. The wet fabric was heated in a forced draft oven for minutes at 140 C. and then removed and washed and air dried. The fabric was. very strong and was flame resistant.

Example 2 Ethylene glycol with APS.-Twenty-five parts of APS were dissolved in parts of ethylene glycol and then the solution was divided into equal parts--Aand B. Concentrated hydrochloric acid was added to part A to reducethe pH to about 5.0; no catalysts were added .to part B. Both 'A and B samples were then heated on the steam bathfor one hour. Then a thin 'film of each of the viscous products was placed upon a glass surface and. heated at 140 C. for 5 minutes. In both cases a clear insoluble film formed on the surface of the glass. Small portions of the film were removed and found to contain phosphorus The term APO refers to.

I and. nitrogen and. were flame resistant. The. films were brittle.

Example 3 were heated together, without solvent, for a few minutes;

at 145 C. the reaction become so vigorous that sufficient heat was produced to decompose the products that were formed.

Example 4' Z-amino-Z-methyl-I,3-pr0panedi0l with APS.-A solution was prepared by dissolving 30 parts of APS and 17 parts of 2-amino-2-methyl-l,3 propanediol in 188- partsof water. The pH of the solution was 1.0.0. A straw colored polymer formed when the solution was heated for a few minutes on the steam bath. The polymer became much harder but did not discolor when heated in-an oven at 150 for 5 to 10 minutes. The polymer was highly flame resistant and contained phosphorus and nitrogen.

Example 5 Tris(hydroxymethyl) aminomethane with APS.-A solution was made by dissolving 30 parts of APS and 19 parts of tris(hydroxymethyl)aminomethane in 200 parts of Water. A hard, clear polymer was produced by-heating the solution on a steam bath for a few minutes. The resin became slightly'more'brittle when itwas heated in anoven at 110 or at 170 for 5 minutes.

When a piece of cotton fabric was wet in the above aqueous solution and then dried at 70 C. and cured for 5 minutes at 150 C., the fabric became flame resistant. It remained strong with a good hand.

Example 6 Ethylene glycol with APO.A solution was prepared containing 5 parts APO, 2.7 parts ethylene glycol and 3 parts water. Sodium carbonate was added to givea pH.

of 8.0 to 8.5. The solution was heated for 2.5 hours on a steam cone, allowing no water to evaporate. After standing at room temperature overnight the viscous mixture was cured for 45 minutes at C. allowing the water to evaporate. A clear colorless rubbery polymer was formed. Further curing in thin films (1 to 2 mm. thick) at 145 C. for 10 minutes produced a hard, clear colorless polymer insoluble in boiling water and acetone. Films of polymer of 4 to 5 mm. thickness when heated at 145 C. decomposed with the evolution of dense white fumes.

Example 7 2-butene-1,4-di0l with APS.A clear solution was prepared by dissolving 30 parts of APS in 21 parts. of warm 2-butene-l,4-diol. The solution was spread out intov a thin layer (about 2 mm. thick) and then heated at. C. for 30 minutes to produce a clear, solid resinous prodnot that was insoluble in water. The resinous product was heated an additional 5 minutes at C. The polymer became a tough, flexible resin. It had a very light amber color. A thin sheet of this resin would burn when ignited with a match although it contained phosphorus and nitrogen.

We. claim:

1. A process for rendering a hydrophilic organie'fiorous material flame-resistant which comprises impregnating said fibrous material with a homogeneous aqueous iiquid mixture containing a l-aziridinyl compound selected from the group consisting of tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol of the formula R(OH),, where x is an 1nteg er of at least 2 and R is selected from the group consisting of unsubstituted and amino-substituted alkyl radicals, the proportions of l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, and heatmg the impregnated material to a temperature of about from 100 to 170 C. to produce a flame-resistant polymer in and on the fibers of the material.

2. A process for rendering a hydrophilic organic fibrous material flame-resistant which comprises impregnatlng said fibrous material with a homogeneous aqueous liquid mixture containing a l-aziridinyl compound selected from the group consisting of tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol of the formula R(OH) where x is an integer of at least 2 and R is selected from the group consisting of unsubstituted and amino-substituted alkyl radicals, the proportions of l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, drying the impregnated material at a temperature of about from 70 to 110 C., and then heating the dried material to a temperature of about from 100 to 170 C. to produce a flame-resistant polymer in and on the fibers of the material.

3. A process for rendering a hydro-philic organic fibrous material flame-resistant which comprises impregnating said fibrous material with a homogeneous aqueous liquid mixture containing a l-aziridinyl compound selected from the group consisting of tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol selected from the group consisting of ethylene glycol, pentaerythritol, tris (hydroxymethyl) aminomethane, 2- amino-Z-methyl-1,3-propanediol, triethanolamine, and diethanolamine, the proportions of l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, and heating the impregnated material to a temperature of-about from 100 to 170 C. to produce a flame-resistant polymer in and on the fibers of the material.

4. A process for rendering a hydrophilic organic fibrous material flame-resistant which comprises impreg' nating said fibrous materialwith a homogeneous aqueous liquid mixture containing a l-aziridinyl compound selected from the group consisting of tris(1-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol selected from the group consisting of ethylene glycol, pentaerythritol, tris (hydroxymethyl) aminomethane, 2 amino 2 methyl 1,3 propanediol, triethanol-amine, and diethanolamine, the proportions of l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, drying the impregnated material at a temperature of about from 70 to 110 C., and then heating the dried material to a temperature of about from 100 to 170 C. to produce a flame-resistant polymer in and on the fibers of the material.

5. A process for rendering a hydrophilic organic fibrous material flame-resistant which comprises impregnating said fibrous material with a homogeneous aqueous liquid containing a partially polymerized product obtained by warming a homogeneous liquid mixture of a l-aziridinyl compound selected from the group consisting of tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol of the formula R(OH), where x is an integer of at least 2 and R is selected from the group consisting of unsubstituted and amino-substituted alkyl radicals, the proportions of l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, and heating the impregnated materialto a temperature of about from 100 to 170 C. to produce a flame- "resistant polymer in and on the fibers of the material.

6. A process for rendering a hydrophilic organic fi brous material flame-resistant which comprises impregnating said fibrous material with a homogeneous aqueous liquid containing a partially polymerized product obtained by warming a homogeneous liquid mixture of a l-aziridinyl compound selected from the group consisting of tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol of the formula R(OH) where x is an integer of at least 2 and R is selected from the group consisting of unsubstituted and amino-substituted alkyl radicals, the proportions of l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, drying the impregnated material at a temperature of about from 70 to 110 C., and then heating the dried material to a temperature of about from to 170 C. to produce a flame-resistant polymer in and on the fibers of the material.

7. A process for rendering a hydrophilic organic fibrous material flame-resistant which comprises impregnating said fibrous material with a homogeneous aqueous liquid containing a partially polymerized product obtained by warming a homogeneous liquid mixture of a l-aziridinyl compound selected from the group consisting of tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol selected from the group consisting of ethylene glycol, pentaerythritol, tris (hydroxymethyl) aminomethane, 2-amino-2-methyl 1,3-propanediol, triethanolamine, and diethanolamine, the proportions of. l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, and heating the impregnated material to a temperature of about from 100 to 170 C. to produce a flame-resistant polymer in and on the fibers of the material.

8. A process for rendering a hydrophilic organic fibrous material flame-resistant which comprises impregnating said fibrous material with a homogeneous aqueous liquid containing a partially polymerized product obtained by warming a homogeneous liquid mixture of a l-aziridinyl compound selected from the group consisting of tris (l-aziridinyl) phosphine oxide and tris (l-aziridinyl) phosphine sulfide and an alcohol selected from the group consisting of ethylene glycol, pentaerythritol, tris (hydroxymethyl) aminomethane, 2-amino-2-methyl-1,3-propanediol, triethanolamine, and diethanolamine, the pro portions of l-aziridinyl compound and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, drying the impregnated material at a temperature of about from 70 to C., and then heating the dried material to a temperature of about from 100 to C. to produce a flame-resistant polymer in and on the fibers of the material.

9. A process of reducing the flammability of a cotton textile material which comprises impregnating said material with an aqueous solution containing tris (l-aziridinyl) phosphine sulfide and pentaerythritol, the proportions oftris (l-aziridinyl) phosphine sulfide and pentaerythritol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, drying the impregnated material at a temperature of about from 70 to 110 C., and then heating the dried material to a temperature of about from 100 to 170 C. for about from 2 to 10 minutes, using the longer time with the lower temperature.

10. A process of reducing the flammability of a cotton textile material which comprises impregnating said material with an aqueous solution containing tris (l-aziridinyl) phosphine oxide and pentaerythritol, the proportions of tris (l-aziridinyl) phosphine oxide and pentaerythritol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group, drying the impregnated material at a temperature of about from 70 to 110 C., and then heating the dried material to a temperature of about from 100 to 170 C. for about from 2 to minutes, using the longer time with the lower temperature. v

11. A process of reducing the flammability of a cotton textile material which Comprises impregnating said materialwith'an'aqueou's solution containing tris (l-aziridinyl) phosphine sulfide and tris (hydroxymethyl) aminomethane, the proportions of tris "('l-aziridinyl) 'phos'phine sulfide and tris (hydroxyrnethyl) aminornetha'ne being such that from 1 to 2 alcoholic -'OH groups are present for each l-aziridinyl group, drying theimpregnated material at a temperature of about from 70 to 110 C., and then heating the dried material to atempera'ture of about 100 to 170 C. for about from2 to 10'minute's, using the longer time with the lower temperature.

12. A process of reducing the flammability of a cotton textile material which comprises impregnating said material with an aqueous solution containing tris ('l-aziridinyl) phosphine sulfide and 2-amino-2-methyl-1,3-propanediol, the proportions of tris l-aziridinyl) .phos'phin'e sulfide and Z-amino-Z-methyl-l,3-propanediol being such that from 1 to '2 alcoholic OH groups are present 'for each l-azir idinyl group, drying the impregnated material at a temperature of about from 70 to 100 C., and then heating the dried material to a temperature of aboutv from 100 to 170 'C. for about from 2 to 10 minutes, using the longer time with the lower temperature.

13. A process of reducing the flammability of a cotton textile material which comprises impregnating said material with an aqueous solution containing tris ('l-aziridinyl) phosphine sulfide and triethanolamine, the proportions of tris (l-aziridinyl phosphine sulfide and trie'thanolamine being such that from 1 to '2 alcoholic OH groups are present for each l-azir idiny'l group, drying the impregnated material at a temperature of about from 70 to aziridinyl) phosphine sulfide and an alcohol selected fromthe group consisting of ethylene glycol, pentaerythritol, tris (hydroxymethyl) -aminomethane, 2-amino-2-methyl- 1,3-propanedio-l,trie'thanolamine, and diethano lamine, the proportions of l-aziridinyl compounds and alcohol being such that from 1 to 2 alcoholic OH groups are present for each l-aziridinyl group.

15. The product of claim 14 in which the hydrophilic organic fibrous material is cotton.

References Cited in the file of this patent UNITED STATES PATENTS 2,606,901 Parker Aug. 12, 1952 2,654,738 Lecher Oct. 6, 1953 2,660,543 Walter Nov. 24, 1953 2,668,096 Reeves et a1 Feb. 2, 1954 2,672,459 Kuh Mar. 16, 1954 2,682,521 Coover June 24, 1954 FOREIGN PATENTS 854,651 Germany Nov. 6, 1952 863,055 Germany Jan. 15, 1953 888,853 Germany Sept. 7, 1953 

1. A PROCESS FOR RENDERING A HYDROPHILIC ORGANIC FIBROUS MATERIAL FLAME-RESISTANT WHICH COMPRISES IMPREGNATING SAID FIBROUS MATERIAL WITH A HOMOGENEOUS AQUEOUS LIQUID MIXTURE CONTAINING A 1-AZIRIDINYL COMPOUND SELECTED FROM THE GROUP CONSISTING OF TRIS (1-AZIRIDINYL) PHOSPHINE OXIDE AND TRIS (1-AZIRIDINYL) PHOSPHINE SULFIDE AND AN ALCOHOL OF THE FORMULA R (OH) WHERE X IS AN INTEGER OF AT LEAST 2 AND R IS SELECTED FROM THE GROUP CONSISTING OF UNSUBSTITUTED AND AMINO-SUBSTITUTED ALKYL RADICALS, THE PROPORTIONS OF 1-AZIRIDINYL COMPOUND AND ALCOHOL BEING SUCH THAT FROM 1 TO 2 ALCOHOLIC -OH GROUPS ARE PRESENT FOR EACH 1-AZIRIDINYL GROUP, AND HEATING THE IMPREGNATED MATERIAL TO A TEMPERATURE OF ABOUT FROM 100* TO 170*C. TO PRODUCE A FLAME-RESISTANT POLYMER IN AND ON THE FIBERS OF THE MATERIAL. 